We have been taught our whole lives to "look out for number one". We cannot trust the world to instantaneously meet our physical and emotional needs. If we don't take care of ourselves, who will? This lesson is about correcting the notion that we know what is best for us and introduces the theme of humility.
The first paragraph is a slap in the face to the ego.It essentially says we have no guide because we have chosen ourselves as a guide. As it says in the text, "Resign now as your own teacher." (T-12.V.8:3) and "Remember nothing that you taught yourself, for you were badly taught." (T-28.I.7:1). Jesus is asking us to admit we don't understand anything and to let him teach us. This is challenging because of the part of us that believes we know what is best for ourselves.
We would have to truly know what our probelms, needs and desires are in order to know what in is our best interest. But as we have seen, the world and our bodies are literally made as a way of hiding the real problem of separation. In other words, our perceived needs and problems are a smoke screen to keep us focused on the physical and pcychological needs of the body. This distracts us from the mind where the real problem and answer can be found.